• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.570-575
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• 2002

This paper presents a new circular curve fitting approach of articulated manipulators, based on pseudoinverses. The paper aims at gaining the interpolation of circle from n data points, under the condition that the fitted circle should pass both a start point and an end point. In this paper, two algorithms of circular interpolation are presented. Prior to circular interpolation, are a spherical fitting should be performed, using least squares. In the first algorithm, the relationship between point data and normal vector on the sphere is used. In the second algorithm. the equation of plane which can be obtained from 3 points, i.e., a start point, an end point, and center of a sphere. The proposed algorithms are show to be efficient by using MATLAB-based simulation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.1-7
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• 2001

It is very important to test circular motion accuracy of NC machine tools as it affects all other machines machined by them in industries. In this paper, it has become possible to detect errors of linear displacement of radial directions for circle tar motion accuracy test using newly assembled magnetic type of linear scale so called Magnescale ball-bar system. It has also organized computer program systems using tick pulses come out from computer for getting error motion data at colt start time interval in circular motion test on NC lathe. Error data gotten from test is expressed to plots and analysed to numerics by various statistical treatments.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1642-1647
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• 2004

In this article, we present the development of the automated system for adjusting the 6 D.O.F circular fixator. The system includes scheduling software to adjust the Hexapod Circular Fixator (HCF) and an automated strut system with the ability of the multiple synchronized motion. HCF was designed to control a 6 degree-of-freedom Ilizarove fixator and it's mechanism is known as the Stewart Platform. HCF scheduler evaluates each value of altered length of the HCF struts to correct the complex skeletal deformity by using the X-ray data of the patient. The data of HCF scheduler feed into the automated strut system which be able to provide the scheduled adjustment and the automated strut is synchronized by input data.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.141-144
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• 1998

An L-band omnidirectional circular polarized wave antenna is designed and evaluated for transmitting/receiving of vehicle data. Conventional linear polarized wave antenna can not reveive clearly all of the vehicle data which come from the wide driving test range on account of distortion. To overcome this problem, an omnidirectional circular polarized wave antenna is required for the design, first of all, the characteristics, design principle and theoretical background of circular polarized wave with a little signal loss have been reviewed. The designed antenna characteristics an analysed and compared to the desired ones. Our results demonstrate that the strength of vehicle data is flat enough over the full test range using this new antenna.

• Journal of Korean Society of Transportation
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• v.25 no.4
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• pp.109-121
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• 2007

In this study, an imputation model using circular probability distribution was developed in order to overcome problems of missing data from a traffic survey. The existing ad-hoc or heuristic, model-based and algorithm-based imputation techniques were reviewed through previous studies, and then their limitations for imputing missing traffic volume data were revealed. The statistical computing language 'R' was employed for model construction, and a mixture of von Mises probability distribution, which is classified as symmetric, and unimodal circular probability were finally fitted on the basis of traffic volume data at survey stations in urban and rural areas, respectively. The circular probability distribution model largely proved to outperform a dummy variable regression model in regards to various evaluation conditions. It turned out that circular probability distribution models depict circularity of hourly volumes well and are very cost-effective and robust to changes in missing mechanisms.

• Journal of the Korean Data and Information Science Society
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• v.20 no.4
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• pp.757-764
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• 2009

In discriminant analysis, we consider a special pattern which contains a block of missing observations. We assume that the two populations are equally likely and the costs of misclassification are equal. In this situation, we consider the bootstrap confidence intervals of the error rate in the circular models when the covariance matrices are equal and not equal.

• Geomechanics and Engineering
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• v.6 no.4
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• pp.321-340
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• 2014

Uplift response of symmetrical circular anchor plates has been evaluated in physical model tests and numerical simulation using Plaxis. The behavior of circular anchor plates during uplift test was studied by experimental data and finite element analyses in loose sand. Validation of the analysis model was also carried out with 50 mm, 75 mm and 100 mm diameter of circular plates in loose sand. Agreement between the uplift responses from the physical model tests and finite element modeling using PLAXIS 2D, based on 100 mm computed maximum displacements was excellent for circular anchor plates. Numerical analysis using circular anchor plates was conducted based on hardening soil model (HSM). The research has showed that the finite element results gives higher than the experimental findings in the loose sand.

• Journal of Information Technology Applications and Management
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• v.29 no.5
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• pp.1-12
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• 2022

This research is situated at the intersection between industry 4.0, circular economy and tourism, in an attempt to observe the fourth industrial revolution at the service of the application of circular economy principles in the tourism industry. This approach has gained importance due to the COVID-19 pandemic, which has accelerated fundamental dynamics of change linked to business digitization and environmental sustainability. Within the theoretical framework delimited by the aforementioned intersection, the 'goCircular Radar' project, launched by 'TheCircularLab', from Ecoembes (Spain), has been taken as an empirical reference. Among the 165 startups in the circular economy sector, special attention has been paid to those that are oriented, or have a potential application, to tourism. The activities they carry out are described, with particular attention to the technologies they use and their contribution to circularity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.12
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• pp.983-991
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• 2009

The heat transfer phenomenon was investigated in this study when a circular water jet with low velocity flows to the downward facing heated circular plate and against the direction of gravity. Data are presented for jet flow rate between 0.23 and 2.3 l/min, jet fluid temperature of 24$^{\circ}C$, heat fluxes between 345 and 687 W/m$^2$, H/D=1, 2 and 3 with a single round jet diameter 2mm. The effects of heat flux, jet velocity and H/D on the local heat transfer are investigated in for the various regions of jet impingement. The local heat transfer distributions are analyzed based on the visualization of jet flow field. Data from experimental results are correlated by expressions of the form Nu=0.01$Re^{0.58}{\cdot}Pr^{0.4}$.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.228-231
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• 2008

For a satellite data communication, the technology of frame synchronization is widely used between a sender and a receiver. Last year, we suggested zero-loss frame synchronization [1] using pattern search and using bits threshold search algorithm that is based on SIMD technology [2,3]. This algorithm could solve both of hardware and software drawbacks, which are frame loss and low processing performance. However, this algorithm didn't optimize the processing of output data, synchronized data, which caused overhead to the memory allocation and the memory copy. Consequently, the performance of the frame synchronizer application was degraded. In this paper, we enhance previous work using a circular buffer in order to optimize the output data processing. The performance comparison with the previous algorithm shows that the enhanced proposed approach dramatically outperforms in the output data processing speed.